Creating convolution files for Roon in the new Room EQ Wizard (REW) with Inversion


So, I’m desperate now, and I need to reach out for help. I have tried over 10 hours to make sense out of some of these things, but with no success.

First question is, is it normal that the impulse response moves without you moving the mic or touching anything. I don’t understand the point of trying to move your speakers 1 mm or whatever it is when every time you redo the measurement, it extends or changes. I have always used distance lasers to get my speakers accurate because I find it considerably more reliable with repeatable results. I use a umik-1 mic.

I would assume that you don’t need to do super long sweeps to make use of the timing reference for an impulse response, correct?

I have a bunch more questions, but I’ll just start off simple.


Are you ticking adjust clock with acoustic reference option? USB mics have timing issues and especially longer sweeps will deviate without it. Even when ticked, some variation from measueemt to measurement is possible but should be less than 1mm. You can use the new 64k sweeps for best timing precision.

Yes, I have that option clicked.

Here’s a picture of the variance I get…. Is this normal?

This is just taking the same measurement over and over again.


OK. I did get everything up and running and playing in Roon…but I think it’s clipping. And I don’t mean the clipping indicator, but I could hear the distortion.

Should I just add headroom then, to Roons setting?

Thanks so much?

That’s a variation of about 2 microseconds between measurements which is less than a millimeter. This is normal and actually a great achievement by John given the clock deviations caused by the USB mic interface. The only way to remove even that kind of deviation is to use an analogue measurement mic with a microphone amp.

Yes. I usually need to add like 6dB headroom myself although I don’t hear any difference, Roon has a very sensitive clipping detector. But if you are hearing something strange, it could be ringing. You may need to check your applied method for the creation of filters. Send me your mdat and I can have a look.

REW file

thank you so much

The distortion I’m hearing happens on bass notes, and Roon needs at least 6db of headroom before i cant really hear it anymore…and 10db of headroom before roons clipping indicator stops showing clipping.

right speaker correction filter (R-inverted MP) is 2.7 seconds off…You must have entered a value in the IR windows Ref Time box by mistake. What are your speakers?

Really? My speakers are buchardt s400 mk2.

Man, I followed the PDF as closely as I could… but there was a lot of stuff, so I suppose I could’ve made a mistake.

How do I correct it?

You don’t need to. I made the filters for you already:

No need to zip it, Roon can read .wav directly when it’s a single stereo convolution.

Don’t forget to adjust headroom for clipping.

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You are the best my friend!

Thank me after you test them :slight_smile:

Apparently s400 and s400 mk2 have different crossover frequencies. I had to make a small change and this one should have a higher sound stage:

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Very interesting. Not sure if it’s placebo, but… it definitely sounds like the soundstage moved up a bit. Very cool.

Is there any way you could send me the REW file. In case I wanted to make changes to the house curve. I’d really appreciate it.

Also, do you have some way that we could send you money… out of our appreciation?

Thank you again

OCA? Love the videos your creating on YT. Still a rookie but, learned much for your tutorials.

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Your speakers have an 8th order crossover @ 1800Hz. When the phase shift this XO causes is corrected, tweeter and woofer signal arrives at the LP at the same time and the sound stage forms at the level of the higher driver.

Your mdat and rePhase settings to create the xo phase shifter are all in this zip:

To increase or decrease the level of the bass, all you need to do is increase/decrease the slope (0.7) in the target curve circled in red below and then match response to target:

The technique is a bit different to inversion but same principle.

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By the way, 0.7 slope is perfect for 75dB volume level. If you think bass is not enough, just turn up the volume. We hear bass frequencies louder than the others when volume increases. I’d only increase 0.7 if I listen regularly at low levels (which I have to do at nights unfortunately!)

Once again, I can’t thank you enough.

So a couple more related questions.

I’m actually planning on picking up a NOS dac, in the very near future. Right now I’m using a denafrips Venus 2.

I would probably have to redo the measurements if I did that, correct?

Also, when I did the measurements using the Venus, I kept the filter mode with my preferred slow setting…. But heard that the sharp measured better. Would it have been better to use the sharp?

Thanks for any input you can offer

I am pretty certain a different dac would not change your REW measurements or filters. The microphones are far less sensitive than any difference a DAC will make. The lowpass filter slope rolloffs you mention are probably happening way beyond 24kHz in the upsampled versions. If you’ve bat ears, you might hear some tonality difference in the very high frequencies but the filters I made for you do not change anything beyond 500Hz anyway so no worries there.